Once Upon a Snowman is a 2020 American animated fantasy short film produced by Walt Disney Animation Studios and written and directed by Trent Correy and Dan Abraham. Correy drew inspiration from a scene where Elsa created Olaf while working on Frozen (2013). He and his team sought to maintain continuity and explore afresh perspective on the original scenes. The short film was released exclusively on the streaming service Disney+ on October 23, 2020. Set during the events of Frozen, Once Upon a Snowman follows Olaf's early adventures to discover his identity after he was created by Elsa, before he met Anna, Kristoff, and Sven.

Kristoff is a fictional character in Walt Disney Animation Studios' Frozen franchise. He appears in the animated features Frozen (2013) and Frozen II (2019), and the animated short films Frozen Fever (2015), Olaf's Frozen Adventure (2017) and Once Upon a Snowman (2020). He was created by co-directors Chris Buck and Jennifer Lee and is voiced primarily by Jonathan Groff.